Re: [PATCH v2 9/9] perf pmu: Fix race with concurrent tracepoint creation and removal in perf list

[sashiko-bot@kernel.org]

> perf_pmus__print_pmu_events() first counts events via
> perf_pmu__num_events() to allocate the aliases array, then populates it
> via perf_pmu__for_each_event(). When dynamic tracepoints (such as
> kprobes or uprobes during 'perf test' runs) are concurrently created or
> removed between the two passes:
> - If an event is removed, state.index is smaller than the allocated len,
>   leaving trailing zeroed entries in aliases[] with name == NULL and
>   pmu == NULL, which causes qsort(cmp_sevent) or the print loop to crash
>   with SIGSEGV.
> - If a dynamic tracepoint subsystem directory is removed while scanning
>   /sys/kernel/tracing/events, tp_pmu__for_each_tp_event() returns
>   -ENOENT and aborts enumeration of all remaining tracepoint subsystems.
> - If an event is added, perf_pmus__print_pmu_events__callback() aborts
>   enumeration when state->index reaches state->aliases_len.
> 
> Grow state->aliases dynamically via realloc() when needed, use
> state.index as the actual populated length for sorting and printing, and
> ignore -ENOENT when a tracepoint subsystem directory disappears during
> enumeration.
> 
> Fixes: c3245d2093c1 ("perf pmu: Abstract alias/event struct")
> Fixes: 45b6e281cb06 ("perf tp_pmu: Add event APIs")
> Assisted-by: Antigravity:gemini-3.1-pro
> Signed-off-by: Ian Rogers <irogers@google.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260929062937.374137-1-irogers@google.com?part=9